Effects Of Management Regime On Growth And Soil Fertility Of Torreya Grandis Cv.merrillii Plantations

Torreya grandis cv.merrillii is a variety of Torreya grandis.It is a famous nut tree species and unique to China.In recent years,with the continuous improvement of the economic value of Torreya grandis cv.merrillii cultivation,its management measures have been farther improved.The Torreya grandis cv.merrillii industry is developing rapidly.Understanding the impact of different forest management measures on Torreya grandis cv.merrillii growth and soil fertility can provide a basis for the healthy development of this industry.In this study,an investigation was conducted to reveal the different management measures on Torreya grandis cv.merrillii growth and soil fertilization.The main results are as follows.(1)Different management measures can significantly increase soil EC,NO3--N,P,Ca and DON in Torreya grandis cv.merrillii stands.The normal management with goose breeding was the best for soil fertility compared to the controls and normal management.There were no significant differences in soil pH among different management measures,indicating that different management measures have little effect on the soil pH.The differences in nutrients between managed and unmanaged blocks were not significant,because soil in the unmanaged block was not easily lost,and the soil pH,K,SOC and TN contents were somewhat higher than the two management measures.This may be attributed to better soil and water conservation in the unmanagement stand without soil reclamation and removal of ground vegetation.(2)The SWC,EC,SOC,TN,Mg and MBC contents were significantly different between different slope aspects.The SWC was higher on the northwest(shady slope)than on the southwest(sunny slope).The contents of SOC and TN decreased with soil depth.The SOC and TN were higher on the southwest than on the northwest.The Mg content was higher on the northwest than on the southwest.The differences of soil pH and MBC was not significant between the different slope aspects.In 0-30 cm soil depth,the pH and Ca are the main factors affecting soil fertility.Different slope aspects have great influence on soil fertility in 20-30 cm soil layer,with obvious spatial heterogeneity.(3)In this study,it was found that stand age had significant impact on soil fertility.With the increase of stand age,the soil fertility increased to some extent.There are significant differences in soil physical and chemical indicators in different aged stands.With the increase of forest age,the soil fertility has been improved to some extent.Fertilization significantly increased the contents of SOC,TN and P and the differences between the soil layers were not significant.Fertilization significantly increased soil Ca content.The soil pH decreased with the increase of stand age,indicating an acidification trend as stand development.